The present invention relates to a cassette for packaging containers of flexible material, the cassette having two opposing walls.
Packaging containers for consumer products, and in particular foods such as dairy products, creams or purees are often manufactured from flexible material which is cut, folded and thermosealed to form a finished packaging container, for example of parallelepipedic configuration. One type of packaging container which at present is available on the market is thus manufactured from a flexible packaging laminate which includes a carrier or core layer of fibre material (paper) which, on either side, is coated with layers of thermoplastic material, e.g. polyethylene or some type of plastic. The packaging laminate also often includes barrier layers of metal (aluminium foil) or plastic material in order to ensure that the packaging container receives the desired gas- and bacteria tightness.
A plurality of different filling machines for manufacturing these or similar types of packaging containers are known in the art. Many of these operate with semi-manufactures, e.g. tubular packaging container blanks, which are fed into the machine in the flat-laid state, but are erected so as to obtain a preferably square or rectangular cross section when they are fed into the filling machine. During movement through the filling machine, the packaging containers are progressively provided with a liquid-tight bottom which may be in the form of a separate bottom portion which is connected to the tubular packaging container portion or constitutes a part of the packaging container separated off by means of crease lines, this part being folded and thermosealed for the formation of a liquid-tight bottom. The packaging container is thereafter moved on to a filling station in which the desired type of contents are filled into the packaging container, whereafter its as yet open end is closed and sealed. This may take place by means of a separate portion or in that this packaging container end is also provided with end wall panels which are separated by means of crease lines and which are folded together and sealed for the formation of a tight packaging container end wall. The packaging container may possibly be provided with some form of opening arrangement and, after application of this opening arrangement, and possible final forming, the filled packaging container is finished and discharged from the filling machine.
Each individual packaging container which is moved through a filling machine of this type is preferably carried by some form of conveyor which ensures that the packaging containers are displaced between different stations for bottom forming, filling and top forming. In its simplest form, the conveyor may consist of a standard conveyor belt with some form of carriers, e.g. strips or fingers. In more sophisticated filling machines operating at high speed and with rapid accelerations, it is, however, of vital importance that the individual packaging containers be both placed and maintained in the correct position for the different operational phases, for example end closure and filling, and increasingly stringent demands are therefore being placed on the ability of the conveyor to move the individual packaging containers from station to station with precision and rapidity. It is, therefore, now common that each individual packaging container is supported by a cassette which, on at least two sides, surrounds the packaging container and fixes it in an accurately predetermined position in relation to the conveyor and the different stations.
Apart from the accurate positioning of each individual packaging container in the longitudinal and transverse directions of the conveyor, it is, in particular in mechanical processing, for example bottom or top sealing of the packaging container, also of major importance that the vertical position of the packaging container be accurately defined when it is located on the conveyor. This takes place in prior art conveyors normally in that each cassette is provided with a bottom against which the lower end of the packaging container rests, or in that the lower end of the cassette is open so that the lower end of the packaging container can rest on stationary guides or sliding surfaces. Both of these systems suffer from a number of drawbacks.
In prior art conveyors of the type which includes cassettes with a fixed or movable bottom, this will limit accessibility to the end of the packaging container facing towards the bottom and it will thus become necessary to carry out any possible processing phases already before the packaging container is placed in the cassette. Insertion and removal, respectively, of the packaging container in the cassette must also take place from above or from the side, since the cassette bottom prevents insertion of the packaging container from the lower end of the cassette. In packaging containers of the type in which the bottom is formed by folding, forming and sealing of end wall panels defined by means of crease lines on the packaging container, the configuration of the bottom will, moreover, not be so well defined, with the result that the surface which abuts against the bottom of the cassette may have a physical form which varies within certain limits. This entails that the vertical position of the packaging container in the cassette may vary such that its upper end may be located a few millimetres higher or lower than the desired position, which is of particularly serious disadvantage when end wall panels at the upper end of the packaging container are to be folded and sealed for the formation of the upper end wall of the packaging container.
In the type of conveyors which include cassettes without a bottom surface, a packaging container placed in the cassette will instead slide with its lower end against stationary guides or surfaces, which makes it possible to access the lower end of the packaging container, for example for bottom formation or other processing while the packaging container is located in the conveyor. However, this sliding against such sliding surfaces entails a certain friction which, in long transport distances and/ or fragile packaging material, may result in damage, for example that the liquid-tight surface layer or the artwork decor on the outside of the packaging container is exposed to wear which negatively affects the performance or appearance of the finished packaging container. If the packaging container, as is often the case, is placed inverted in the cassette in order to make for filling at the bottom end of the packaging container, the downwardly facing top end of the packaging container is often provided with some type of projecting opening arrangement, for example a lid of plastic material which, in such an event, is subjected to unnecessary wear which, while not in itself damaging or affecting the function of the opening arrangement, may result in the opening arrangement having a worn or distressed appearance. Also in that type of packaging conveyor which includes fixed guides or sliding surfaces, the placing of the packaging container in the vertical direction may be slightly varying, which entails the previously mentioned drawbacks on processing of the opposite, temporarily upper end of the packaging container. There is also a risk that the sliding surface or guides accumulate impurities or scrapings from the packaging paperboard which then adhere to a part of the outsides of the finished packaging containers.
There is thus a general need in the art to realise a cassette by means of which a packaging container of flexible material may be transported through a filling machine in a reliable and accurately fixed manner without the above-outlined drawbacks occurring.
One object of the present invention is therefore to realise a cassette for packaging containers, the cassette being constructed such that it is simple to insert and remove packaging containers and that a packaging container placed in the cassette will be reliably fixed in the correct position and with the correct orientation.
A further object of the present invention is to realise a cassette for employment in a per se known conveyor in a filling machine, the cassette making it possible to transport packaging containers between different processing stations in the filling machine without the packaging containers being subjected to unnecessary wear or other damage.
Yet a further object of the present invention is to realise a cassette by means of which a packaging container of flexible material may be fixed in the desired position for displacement through a filling machine without parts projecting from the packaging container being subjected to damage.
Still a further object of the present invention is finally to realise a cassette for packaging containers of flexible material, the cassette being of simple design and construction and lacking moving parts, rendering it therefore operationally reliable and easy to clean.
The above and other objects have been attained according to the present invention in that a cassette for packaging containers of flexible material, the cassette having two opposing walls, has been given the characterizing feature that the walls are located in mutual spaced apart relationship a distance corresponding to the corresponding external dimensions of the packaging container, the cassette including a support member for fixing the packaging container in the correct position in the cassette by cooperation with a flexible portion projecting from the packaging container.
Preferred embodiments of the apparatus according to the present invention have further been given the characterizing features as set forth in the appended subclaims.
By designing, according to the present invention, the cassette with one or more fixed, integrated support device which utilises the flexibility of the packaging container in order to fix the packaging container in the correct position, a complicated design and construction which is difficult to wash and clean may be avoided, at the same time as the cassette has an open construction which makes it possible to move the packaging container into or out of the cassette at both ends thereof